In camping, backpacking, or other outdoor activities, there are various items which should not be exposed to water (e.g. a camera, maps, first aid kit, a cell phone, etc.), and yet these items should be readily accessible to the user. Thus, there is a need to be able to place such items in a waterproof container which is "user friendly", in that it can be easily opened and closed, and yet which provides protection from the water.
In the prior art, there are various waterproof bags where the bag material is given a treatment to make it waterproof. However, this can often be expensive. Also, in outdoor activities, the container can be subjected to sharp objects, impacts, and other forms of abuse, which may damage the waterproof material so that it leaks. A search of the U.S. patent literature disclosed a number of waterproof bags or containers, and also various devices for closing these and other bags. These are as follows:
U.S. Pat. No. 2,435,743 (Geimer) discloses a bag made of three components. There is an outer layer 2, which is formed of a sturdy general-purpose material, and this is not water impervious. There is a second intermediate bag 3 which is made of a waterproof material, and an inner bag component 10 which is formed of porous sheet stock. The reason given for this construction of the inner bag 10 is so that air which is mixed with the material contained in the inner bag 10 can pass out from it in all directions. These bag components are not attached to one another, and the upper end of each is closed separately.
The manner of closing the bag is probably best seen in FIGS. 5 and 6. The innermost bag component 10 is closed by being folded over on itself, as shown in FIG. 5. Then the upper edge of the intermediate waterproof bag is closed in the manner shown in FIG. 4 in one view, and also shown in FIG. 5 in a sectional view taken along line 5--5 of FIG. 4. The upper portion of the intermediate waterproof bag component 3 is then folded over on itself in a manner shown in FIG. 6, and the outer bag 2 is sealed as shown in FIG. 7.
U.S. Pat. No. 4,421,150 (Masters) shows a bag system in which there is a sturdy outer bag "B" of heavy duty nylon or the like, and there is a waterproof inner bag "D". There is a flap "C" secured to the outer bag and this overlaps the end portion of the bag "D". In use, the upper end of the inner bag "D" is rolled as shown in FIG. 3, and then the flap "C" is folded over and secured with a Velcro strap.
U.S. Pat No. 3,315,877 (Grevich) shows a bag that may or may not be provided with an air tight liner (column 1, lines 47 and following). The bag is closed by folding over the lip several times and binding it with a locking strip 18, which would be more similar to your method of closing the bag.
U.S. Pat. No. 3,203,551 (Van Loan) shows a bag closure in which the open end is folded over and secured by a Velcro band that folds around the edge of the bag.
U.S. Pat. No. 4,550,442 (Lepisto) shows a seamless plastic tube placed in a gusseted bag and free to move about.
U.S. Pat. No. 4,343,158 (Campbell) shows a multi-pocket bag with insulated sections for the storage of insulin and other supplies, as well as a pocket for an ice pack or the like.
U.S. Pat. No. 3,674,188 (Anderson) shows a game bag which a burlap bag contains a waterproof bag that holds the game. There are opening in the waterproof bag that holds the game. There are openings in the waterproof bag for drainage, rather that being watertight.
U.S. Pat. No. 2,580,796 (Kleiss et al.) shows a shopping bag that is provided with a moisture proof liner that is secured at only the top which can be pulled completely from the bag.
U.S. Pat. No. 1,982,813 (Jacobi) shows a bag that is closed by rolling over the top, and binding the overlapping layers with a strap. The strap is retained by a lock that passes through openings in the over lapping flaps.
U.S. Pat. No. 1,742,808 (Reach) shows a water bag that is sealed by folding over the top several times, and binding the folded mass with an attached strap.
U.S. Pat. No. 825,455 (Mortensen) shows a bag that is held closed by winding the top of the bag around a length of a flexible strip, which is then joined to itself.
U.S. Pat. No. 814,150 (Manahan) shows a closure system in which the ends of the bag are clamped after being folded over so as to seal the bag.